As a method of epitaxially growing Ge of low defect density on Si, a method of applying a low temperature buffer layer has been known (for example, refer to H-C. Luan, D. R. Lim, K. K. Lee, K. M. Chen, J. G. Sandland, K. Wada and L. C. Kimerling, Appl. Phys. Lett., 1999, vol. 75, pp. 2909-2911).
Further, as another method of forming a Ge layer of low defect density on an Si substrate, an enriched oxidation process has been known (for example, refer to JP-A-2005-142217, and S. Nakaharai, T. Tezuka, N. Sugiyama, Y. Moriyama, and S. Takagi, Appl. Phys. Lett., 2003, vol. 83, pp. 3516 to 3518).
Further, a method of enhancing the crystallinity of a Ge layer by improving the enriched oxidation process has been known (for example, refer to T. Tezuka, N. Sugiyama, and S. Takagi, J. Appl. Phys., 2003, vol. 94, pp. 7553 to 7559).
Further, as a technique of using an epitaxial lateral growth (ELO), a method of growing gallium nitride (GaN) on a sapphire substrate by ELO has been known (for example, refer to JP-A-2000-021789).
Further, a method of growing Ge on Si by ELO has been known (for example, refer to T. A. Lango, C. W. Leitz, M. T. Currie, E. A. Fitzgerald, A. Lochtefeld, and D. A. Antoniadis, Appl. Phys, Lett., 2000, vol. 76, pp. 3700 to 3702).
Further, in a case of manufacturing a Ge photodiode device by utilizing the ELO technique, a method of avoiding coalescence of Ge layers to each other grown from each of by ELO has been known (for example, refer to JP-T-2006-513584 and JP-A-2007-123852).